This data release contains seasonal application estimates of nitrogen and phosphorus to cropland for watersheds draining to the Puget Sound and the Strait of Juan de Fuca, Washington. The data, which cover the years 2005 through 2020, were used as input to seasonal Spatially Referenced Regression On Watershed attributes (SPARROW) total nitrogen and total phosphorus models that were used to assess nutrient loadings to Puget Sound. The values constitute the seasonal nitrogen and phosphorus application for each incremental catchment represented in the SPARROW models.

This data release contains estimated seasonal total nitrogen (TN) and total phosphorus (TP) loads during 2005 through 2020 in selected streams of the watersheds draining to Washington waters of the Salish Sea (Puget Sound region). Two load estimation methods were used: Fluxmaster (Schwarz and others, 2006, https://doi.org/10.3133/tm6B3) and Weighted Regression on Time, Discharge, and Season (WRTDS) with Kalman filtering (Hirsch and De Cicco, 2015, https://doi.org/10.1016/j.envsoft.2015.07.017). Together with the water-quality data, streamflow data, and estimated nitrogen and phosphorus loads, this release also provides copies of computer programming script that can be used to recreate the load estimates or modified for similar applications (see Process Steps). Seasonal TN and TP loads paired with streamflow were estimated at 50 locations. For convenience, seasonal summaries are also provided of observed streamflow at 128 locations and of observed water temperature at 29 locations.

This data release contains seasonal source-specific estimates of total nitrogen (TN) and total phosphorus (TP) loads from watersheds draining to Washing water of the Salish Sea (Puget Sound region,12,314 e2NHDPlusV2 reaches plus 2 added transfer reaches) using a dynamic SPARROW (Spatially Referenced Regressions on Watershed attributes) model. Input data, output predictions, model control files, and model source code are provided to fully reproduce results. The modeled period was from January 2005 through December 2020 in seasonal time steps, or 64 periods, and the following seasonal definitions were applied: winter includes January, February, and March; spring includes April, May, and June; summer includes July, August, and September; and fall includes October, November, and December.

This data release contains monthly deposition estimates of wet and total inorganic nitrogen (reduced and oxidized) for watersheds draining to the Puget Sound and the Strait of Juan de Fuca, Washington. The data, which cover the years 2005 through 2020, were used as input to a seasonal Spatially Referenced Regression On Watershed attributes (SPARROW) total nitrogen model that was used to assess nutrient loadings to Puget Sound and the Strait of Juan de Fuca. The values constitute the monthly nitrogen deposition for each incremental catchment represented in the SPARROW models.

The United States Geological Survey’s (USGS) SPAtially Referenced Regressions On Watershed attributes (SPARROW) model was developed to aid in the interpretation of monitoring data and simulate water-quality conditions in streams across large spatial scales. SPARROW is a hybrid empirical⁄process-based mass balance model that can be used to estimate the major sources and environmental factors that affect the long-term supply, transport, and fate of contaminants in streams. The spatially explicit model structure is defined by a river reach network coupled with contributing catchments. The model is calibrated by statistically relating watershed sources and transport-related properties to monitoring-based water-quality load estimates. Load estimates used in recent Midcontinent SPARROW model applications (2002 base year) are described in Saad and others, 2018 (https://doi.org/10.3133/sir20185051). Load estimation methods described in this report include the Beale Ratio Estimator and Fluxmaster models. This USGS data release, prepared in cooperation with the International Joint Commission, contains all of the input and output files necessary to reproduce the load estimates considered for inclusion in the 2002 Midcontinent SPARROW models. Data preparation for input to the load estimation models is also fully described in the above-mentioned report.

The United States Geological Survey’s (USGS) SPAtially Referenced Regressions On Watershed attributes (SPARROW) model was developed to aid in the interpretation of monitoring data and simulate water-quality conditions in streams across large spatial scales. SPARROW is a hybrid empirical/process-based mass balance model that can be used to estimate the major sources and environmental factors that affect the long-term supply, transport, and fate of contaminants in streams. The spatially explicit model structure is defined by a river reach network coupled with contributing catchments. The model is calibrated by statistically relating watershed sources and transport-related properties to monitoring-based streamflow and water-quality load estimates. Streamflow and load estimates considered for use in regional SPARROW model applications (2012 base year) are described in Saad and others, 2019 (https://dx.doi.org/10.3133/sir20195069). Load estimation methods described in this report include the Beale Ratio Estimator and Fluxmaster models. This USGS data release contains all of the input and output files necessary to reproduce the load estimates considered for inclusion in the 2012 regional SPARROW models. Data preparation for input to the load estimation models is also fully described in the above-mentioned report.

This data release contains estimated monthly point-source nutrient loads for 97 municipal wastewater treatment plants, 20 industrial facilities, and 46 fish hatcheries and other aquaculture facilities that discharge within the watersheds draining to Puget Sound and the Strait of Juan de Fuca in Washington, or discharge directly to those water bodies. The data, which cover the years 2005 through 2020, were used as input to a set of seasonal SPARROW total nitrogen and total phosphorus SPARROW models that were used to assess nutrient loadings to Puget Sound.

This data release contains mean-annual total nitrogen (TN) loads predicted by a SPARROW model for individual stream and shoreline reaches in the Chesapeake watershed as defined by NHDPlus, a 1:100,000 scale representation of stream hydrography built upon the National Hydrography Dataset (NHD) (Horizon Systems, 2010). Also included are the input variables required to execute the model, including landscape characteristics, nutrient inputs to land, and calibration data from water quality monitoring stations. Further details on model construction and results are described in Ator (2011, https://doi.org/10.3133/sir20115167).

The U.S. Geological Survey’s (USGS) SPAtially Referenced Regression On Watershed attributes (SPARROW) model was developed to aid in the interpretation of monitoring data and simulate water-quality conditions in streams across the Midcontinental Region of Canada and the Unites States. SPARROW is a hybrid empirical⁄process-based mass balance model that can be used to estimate the major sources and environmental factors that affect the long-term supply, transport, and fate of contaminants in streams. The spatially explicit model structure is defined by a river reach network coupled with contributing catchments. The model is calibrated by statistically relating watershed sources and transport-related properties to monitoring-based water-quality load estimates. This USGS data release, prepared in cooperation with the International Joint Commission and National Research Council Canada, includes output files representing 2002 SPARROW simulations of total nitrogen and total phosphorus in streams of the Midcontinent. Model calibration and results are described in Robertson and others (2019, https://doi.org/10.1111/1752-1688.12792). Geospatial data used for developing the Midcontinental SPARROW nutrient models are described in Vouk and others (2018, https://doi.org/10.4224/23004810). Model calibration targets used in the SPARROW models are described in Saad and others (2018, https://doi.org/10.3133/sir20185051).

The U.S. Geological Survey's (USGS) SPAtially Referenced Regressions On Watershed attributes (SPARROW version 2_10) model was used to aid in the interpretation of monitoring data and simulate streamflow and water-quality conditions in streams across the Pacific Region of the Unites States. SPARROW is a hybrid empirical/process-based mass balance model that can be used to estimate the major sources and environmental factors that affect the long-term supply, transport, and fate of contaminants in streams. The spatially explicit model structure is defined by a river reach network coupled with contributing catchments. The model is calibrated by statistically relating watershed sources and transport-related properties to monitoring-based water-quality load estimates. This USGS data release includes input and output files associated with 2012 SPARROW simulations of streamflow, total nitrogen, total phosphorus and suspended sediment load in streams of the Pacific region. Model construction, calibration and results are described in Wise (2019, https://doi.org/10.3133/sir20195112). First posted - January 6, 2020(available from author) Revised - June 08, 2020